Mold opening and closing device for an apparatus making hollow bodies from thermoplastic material

ABSTRACT

1. A DEVICE FOR OPENING AND CLOSING MOLD HALVES HELD IN A PAIR OF TONG-LIKE ARM HOLDING ELEMENTS AND FOR MOVING SAME BACK AND FORTH WITH RESPECT TO A MACHINE FRAME BETWEEN A RECEIVING POSITION FOR A MOLDABLE PRE-FORM TO ANOTHER POSITION FOR SHAPING OR BLOWING SAME, COMPRISING: FIRST AND SECOND CARRIAGE MEANS MOUNTED ON SAID MACHINE FRAME AND BEING ADAPTED TO RECIPROCATE IN SAID MACHINE FRAME, A SINGLE DRIVE MEANS ADAPTED TO RESPECTIVELY RECIPROCATE BOTH OF SAID FIRST AND SECOND CARRIAGE MEANS, THE SECOND CARRIAGE MEANS CARRYING SAID MOLD HALVES AND HAVING BRAKE MEANS FOR RESTRAINING THE MOTION OF SAID SECOND CARRIAGE MEANS WITH RESPECT TO SAID MACHINE FRAME, SAID FIRST CARRIAGE MEANS BEING CONNECTED TO SAID SECOND CARRIAGE MEANS AND BEING PROVIDED WITH RESILIENT STOP MEANS FOR ARRESTING THE MOTION OF SAID FIRST CARRIAGE MEANS WITH RESPECT TO SAID SECOND CARRIAGE MEANS AT THE OPEN AND CLOSED POSITIONS OF SAID ARM HOLDING ELEMENTS, AND SAID SECOND CARRIAGE MEANS MOVING FROM ONE POSITION TO ANOTHER POSITION UPON THE CONTINUED RESPECTIVE MOTION OF SAID DRIVE MEANS OVERCOMING SAID RESILIENT STOP MEANS. D R A W I N G

m mas-mas? United States Patent H91 m; 3,854,857 Fischer et al. 1451 D, [7 1974 I MOLD OPENING AND CLOSING DEVICE FOR AN APPARATUS MAKING HOLLOW 5m Hdcrtrcn mm.

BODIES FROM THERMOPLASTIC UNTH) STATES PATENTS MATE'RIAL m ms wwsw Shaman a 425/326 5 [75] lnvcnum; Stehn FLscher. Lnhmar; Prler 2901mm wwsv Pmw 425112! a Gllden. Colognc-Ehrcnfcld. Htlmul JAUZAJI QIIMK Fngclhcrg cu ul v :VDIG 2H5 sch n-rnbrgkh .LF'HSJIH all?! Kudcr cl :1l 425/326 5 X NcumhauS/Sicghurg; mums awn: Flwhu' l 42mm 3 wollwhharrp ns. all Ur FOREIGN PATENTS OR APPLICATIONS mlhml KIWI! Japan 425/010 :05

(73] Assignct: Zlnpro Corportlon. Excelsior. Minn.

. Primary f.'.\um|'nrr-Francis S. Husar 22 F l d: 4, 9'7 u l 1 H: I 3 Assistant Hmnm|erDav1d S. Safran [2|] Appl. No; 3941180 Attorney. Agcnl. Firm-Dowel] and Dflw-ll Rel-ted Us. Application mu I63] (untinuunun 0! Ser, No [42511 M 1 g7 ABSTRACT "Nmhmal A thermoplastic moldlng device comprising mold halves moved by a single drive to both an open and 2 I30] Foreign Application Priority Data closed positiun. and also In a reccivlng position, Mr

Ma |2 1970 Germany. N 2023094 Ewing a p and m H shaping blowing P lion and back Movcmcnl is cnmmllcd by supporting [$21 US. Cl v 415/214. 425/D!(5. 2U. thc mold halves on a carriage means and moving said 4Z51U1U 205 Carnage means with respect in unulhzr carriage means [Si Int. Cl. 82% 5/06 or nun-able framc- [SSI Fkid 0! Starch. l 425/450 R. 450 C. DIG. 22D. 6 Chms 2 pravlnfl Ham,

425/DIG 222. DIG. 205. DIG. 2| 326 B. 214. 2M]! 88 3,85 1 i MOLD OPENING AND CLOSING DEVICE FOR AN APPARATUS MAKING HOLLOW bODIES PROM THERMOPLASTIC MATERIAL This is a continuation of application Ser. No 142.523. filed May l2. l97l. now abandoned.

BACKGROUND OF THE INVENTION The invention relates to devices for making hollow bodies from thermoplastic material. in particular by the blowing process comprising mold halves or grips movable back and forth between a receiving position for a blank or preform and a shaping or blowing position and controllable accordingly to open and close In the known devices of this kind. the closing and opening of the molds or grips and their movement from the receiving position. for the preform. to the blowing position requires special drive elements. for example hydraulic control elements. The closing and opening 'must be controlled in a time sequence. Thus. drive and control means are necessary The object of this invention is to provide a simplified drive device vwhich requires only one drive element for the opening and closing of the molds as well as for the movement of the molds from the receiving position. for the preform. to the shaping position and back.

SUMMARY For this purpose. the invention provides in a device for making hollow bodies from theroplastic materials.

the device having mold halves or grips movable back and forth between a receiving position for a r cldablc preform and a shaping or blowing position a drive elcmcnt which acts directly on control elements for controlling the opening and closing movement of the mold halves and which. with delay. possibly over intermediate devices. takes along in one or the other direction a support for the mold halves whose movement is braked relatively to the machine frame. in order to move it synchronously with the control elements into one or thet other end position In a preferred embodiment the drive element may be. for example. a crank arm or a hydraulic cylinder which acts upon a first carriage. The first carriage is slidable in the machine frame and controls the opening and closing movement of the mold halves. The mold halves are carried by a second carriage disposed in the machine frame. The second carriage is connected to the first carriage with interposition of a certain dead motion and is braked in its movement in Comparison with the first carriage. In one embodiment the first carriage may be coupled with the second carriage by a drive rod. The drive rod has two spaced stops which cooperate with a stop on the second carriage. The second car- Iiage may be provided with an adjustable brake device. The brake device prevents movements of the second carriage with respect to the machine frame until the stops of the drive rod engage the second carriage.

The first'carriage controls the opening and closing movement of the mold halves and comprises twospars displaceably mounted in the machine frame. The spars are connected at their two ends by yolres. The drive element act: directly upon one of these two yokes. The drive rod for the second carriage is then connected with this drive yokev At the other yoke. or respectively .lt'the e'nds of the spars connected therewith. two drive links may be articulated by one end. while at their other ends they are articulatedly connected vvith one of two holding arms. The two holding arms connect the mold halves together in a tong-lilte fashion by a joint. The common joint of these holding arms a arranged upon the second carriage. The length of the drive links should be such that the spars serving for their control lie with their axes approximately at right angles to the longitudinal axis of the links in the closed position of the mold holding arms BRlEF DESCRlPTiON OF THE DRAWlNC'i FIG. I shows the devicepartially sectioned. in elevation; and FIG. 1. a top view. partially sectioned of the device of FIG. I.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the form of execution of the device shown in the drawing. two guides 12 and I) for two spars I4 and 15 are arranged on a bracket ll of the machine frame. At th=ir rear ends the spars I: and 15 are connected together by a yoke Id. The yoke I6 is coupled via a connecting rod 17 to a crank arm [8. The crank arm 18 serves as a drive element and is. in turn. driven by an electric motor 19. The motor [9 is afl'ixed to the bracket ll. The front ends of yokes l4 and 15 are interconnected by a cross-piece 20. Both spars H and 15 are joined by links 2] and 22. respectively. to holding arms 23 and 24 respectively. The holding arms 23 and 24 hold the two mold halves lnot shown) disposed in holding troughs Z5 and 26. The holding arms 23 and 24 are interconnected at a pivot joint 27, so that they can he moved in the manner of tongs.

The oint 27 is carried by a support 28. The support or carriage 28 is displaceahle back and forth o er a predetermined distance upon the bracket II. This carriage type support 28 is retained by a bolt 29 against a guideway on the bracket ll. Tightening of a nut 50 on the bolt 19 (together forming a type of stop means) prevents the displaccmcnt of the support or carriage 1B. Carriage 28 is connected to yoke l6 by means of a drive rod 31. This drive rod 3] is rigidly connected with yoke 16 and extends through an abutment 32. The abutment .32 is affixed upon carriage 28. On the drive rod 3 l stops 33 and .34 are provided spaced a predetermined distance from each other and on either side of the abutment 32 and are resiliently supported by springs 35 and 36. i i

Turning now to the operation of the device. FIG. I shows the position of the parts relatively to each other in the blowing position. in which the preform is shaped to form the finished body and is then ejected. For this the mold must first be opened. For this purpose the crank arm l8 pivots from the position of FIG. I to that of HO. 2. A; a result. the carriage. formed by the spars l4 and IS, the yoke 16. and the cross-piece 20. moves to the right. As this carriage moves. links 2! and 22 move and the holding arms 13 and 24 are pulled apart. Joint 27 at first retains its position on the braked sup port 18. As soon as the stops J3 of the drive rod 3!. strikes against the abutment 32, support 18 moves with the yoke l6. until the crank arm [8 has rotated with respect to its position in FIG. I. Support 28 is ne positioned such that the opened mold halves are in the receiving position for the preform. When the crank arm I8 is then let in motion again. span t4 and [5 are moved via yoke T6 in the opposite direction. The spin I4 and 15 act upon the links 2! and 12 and through these on the holding arms 23 and M for the mold hal es This movement closes the mold halves Meanwhile uint 27 retains its position due to i'ne braking of the support carriage 18. In the closed position of the mold hahes. the links 2| and Z2 reach a position in which their longitudinal axis extends approximatciy at right angles with tne allS of the spars H3 and IS. in the closed position of the mold iiaivcs. the drive rod 37.. connected with yoke l6, has become displaced to the extent that its stop 34 rests against the abutment 32 of support 28. With the further movement of the crank arm l8 into the position according to FIG 1, support 28 for the mold halves is then taken along into the pooltion according to FIG. I, in which the blowing up to the finished body takes place.

We claim:

I. A device for opening and closing mold hal e; held in a pair of lung-like arm holding elements and for moving same brick and forth with respect to a machine frame between a receiving position for a muldahle oreform to another pozitiun for shaping or blowing same. comprising: first and second carriage means mounted on said machine frame and being adapted to recipro tale in said machine frame; a single drive means adapted to respectively reciprocate both of said first and second carriage means; the second carriage mains carrying said mold halves and having brake means for restraining the motion of said second carriage means with respect to said machine frame; said first carriage means being connected to said second carriage means and being provided vmh res iient stop 3l'i5 for arresting fo motion of said first carriag: means with respect to said second carriage means at the own and closed positions of said arm holding elements, and said second carriage means moving from one position to another position upon the curiiinuecrespective motion of said drive means overcoming said resilient stop means 2. The device according to claim I, wherein said brake means is ad ustable so as to compensate for any premature muvemeni of said second carriage means with respect to said first carriage means 3 The (.evcc according to claim 1., wherein said first carriage means comprises a pair of spars and yokes'. said spars being movabiy mounted upon said frame means and connected to said yoites at their ends; and said drive means acting on one of said yokes.

4. The device according to claim 3,1ncluding a drive rod connecting said f-CCOfld carnage means to said one of said yokcs of said first carriage means.

5. The device according to claim i, including a motor driven crank arm element and a connecting rod pivotally connected at it! ends to said crank arm element and said one of said yokes of said first carriage means.

5. Die device according to claim 4. including a pair of drive links. each pivotably connected at its ends to one of said arm holding elements and to the other of said Pklil' of yokes; and said arm holding elements being pivntaoly connected to said second carriage means rbcut a common axis.

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